In the commercial manufacture of thermoplastic polymers, frequently polymer is formed as particles, such as a powder, which must be converted to salable pellets by melting the powder in a batch or continuous mixing device by mechanical shear and auxiliary heating, and passing such molten material to a pelletizer. In such process, the mechanical shear melting step is energy intensive and represents an overall low energy utilization efficiency. A method to decrease the energy use in the melting step would be advantageous for the industry.